He may have served with distinction as head of the Royal Navy, and been a security minister for three years, too. But one thing seems sure about Admiral Lord Alan West: he would never have made a career in the diplomatic service.

On Thursday, he torpedoed the launch of a defence report commissioned by the Labour party with some enlivening, if somewhat intemperate, remarks about two Nato allies.

A strident opponent of cuts to the armed forces, the former first sea lord said the UK was still a first-rate military power, not like "bloody Denmark or Belgium". These countries were, he explained, second-tier powers.

His remarks were pounced on by the Conservatives. The defence secretary, Dr Liam Fox, said Belgium and Denmark had contributed hugely to Nato's efforts in Afghanistan and Libya.

"I'm appalled to hear Lord West insulting Denmark and Belgium, both of whom have been operating alongside British forces in Libya. Forty-two Danes have lost their lives fighting alongside us in Helmand." Fox said.

The controversy had its origins in unlikely surroundings. West was one of three authors commissioned to write a report for Labour on defence procurement – a dry, but important subject that has been the curse of successive governments.

Sensing, perhaps, that concentration was wavering among some of the guests invited to the launch at Labour headquarters in London, West brought the event back to life.

Riled by the suggestion that the UK was a second-tier power, he said: "We are probably, depending on what figures you use, the fifth or sixth wealthiest nation in the world. We have the largest percentage of our GDP on exports … we run world shipping from the UK, we are the largest European investor in south Asia, south-east Asia [and] the Pacific Rim, so our money and our wealth depends on this global scene.

"We are a permanent member of the [United Nations] Security Council and I think that gives us certain clout and certain ability. These mean we are not a second-tier power. We are not bloody Denmark or Belgium and, if we try to become that, I think we would be worse off as a result. I get slightly annoyed at this sort of statement."

The shadow defence secretary, Jim Murphy, tried to make light of it – with an apology. "Thanks Alan, and obviously for any friends from Belgium or Denmark, apologies. Or should I say former friends from Belgium or Denmark?"

Labour officials later stressed that West, 63, was not a member of the party's defence team and his views were not shared by anyone on the shadow frontbench.

"We value his input into the independent review, but his views are his own. He was talking off the cuff and I am sure he didn't mean to cause offence," said one.

West has sailed into political trouble before. As security minister, and adviser to Gordon Brown, he admitted he was not totally convinced that Labour needed to hold terrorist suspects for 42 days. He changed his mind two hours later after some quick reprogramming by the prime minister. "Being a simple sailor, not a politician, maybe I didn't choose my words well," he said of the U-turn.